1. Filed of the Invention
The present invention relates to optical apparatuses having a mirror dividing an optical path.
2. Description of the Related Art
Conventionally, a camera has been disclosed in Japanese Patent Laid-Open Publication No. 2001-125173, which is switchable between an optical viewfinder state and an electronic image display state by moving a half mirror between a first position where the mirror leads light from a taking lens to the optical viewfinder and a second position where the mirror leads the light to an image-pickup device. In this camera, focus detection by the phase difference detection method can be performed in the optical viewfinder state. However, only focus detection by the contrast detection method can be performed in the electronic image display state because the image-pickup device takes images in a state in which the mirror has retreated from the optical path.
In addition, a camera has been disclosed in U.S. patent Laid-Open Publication No. 2004-0155976, in which an optical path dividing system is switchable between a first optical path dividing state and a second optical path dividing state; a light flux from a taking lens is divided into a light flux directing to an optical viewfinder and another light flux directing to a focus detection device in the first optical path dividing state, and the light flux from the taking lens is divided into a light flux directing to an image-pickup device and another light flux directing to the focus detection device in the second optical path dividing state.
According to this camera, the focus detection by the phase difference detection method can be performed not only in the optical viewfinder state (the first optical path dividing state) but also in the electronic image display state (the second optical path dividing state).
In this camera, the focus detection by the phase difference detection method can be achieved in both the optical viewfinder state and the electronic image. However, the common positioning member is used for positioning a sub mirror that reflects the light flux to the focus detection device in the first optical path dividing state and positioning a half mirror that reflects the light flux to the focus detection device in the second optical path dividing state. Therefore, it is difficult to adjust the positioning member for striking a balance between the focus detection performances in the two states.